The invention relates to a hydraulic unit for a hydraulic control device, in particular to a braking pressure control device used in anti-skid or traction slip control systems, having at least one valve block with a group of electromagnetically operable valves and with a connection element for other components of the control device.
The use of electrohydraulic control devices has become more and more widespread in engineering. The reason for this is the possibility of designing the control part of a control system as an electric part and designing the energy part as a hydraulic part. The electromagnetically operated hydraulic valves belong to the boundaries between the electric and hydraulic parts. The valves are combined into assemblies commonly referred to as valve blocks. The assemblies have hydraulic supply and delivery lines and one or more cable outlets.
In commonly owned patent application No. P 3701019.0 a valve block is described for a slip-controlled hydraulic brake system consisting of a valve-receiving element capable of receiving several solenoid valves, a frame, a cover enclosing the frame, and a plug assembly containing a plurality of contact blades, with the solenoid valves connected with the contact blades by means of a contacting foil. The particular feature of this valve block resides in the frame, cover and plug assembly being designed in one piece so as to form a one-piece covering unit permitting the soldering of the contacting foil and fastening in a sealed manner at the valve-receiving element.
German patent application No. P 2303474 and the corresponding U.S. Pat. No. 3,977,625 disclose a pressure medium distributing block with connections for inlet and outlet lines. The connections are provided at least on one side and connected among one another. In each case certain parts of the connection path between the connections are lockable by plugs. In this pressure medium distributing block the connection path between the connections is formed by grooves inserted into the surface of the distributing block.
German published patent application No. P 3529276 and the corresponding U.S. Pat. No. 4,709,945 describe a block-shaped or plate-shaped connection element for connecting the equipment with valves or other components. On the one hand, the connection elements end in an equipment surface adapted for placement of the valves and, on the other hand, the connection element ends in a connection side for connecting a pressure medium line or the like. In the area of an end associated with the connection side, the one flow channel provided at the minimum is connected with a passage channel following the flow channel. The connection of the flow channel is effected by means of both a channel section with a threaded portion extending into its interior and by means of a socket. The socket, e.g., via a further channel section, follows the flow channel coaxially or in parallel with the axis and is shaped in one piece to the connection side from which it protrudes outwardly. The pressure medium line or the like to be connected is alternatively screwable within the threaded portion or mountable onto the socket.
The above-mentioned German patent application No. P 3701019.0 discloses an electromagnetically operable hydraulic valve. Such valves are combined into blocks of two and four, or into multiple blocks. The blocks are standardized and manufactured in large batch quantities. Due to this mass production, the valve blocks become relatively inexpensive. On the other hand, such valve blocks have the following disadvantages in practice.
The pressure medium inlets and outlets are uniformly designed in accordance with set standards. Individual adaptation of the position of the pressure medium inlets and outlets to the components of a hydraulic control device is impossible. Therefore, it is very difficult to use the known valve blocks in order to meet individual client's wishes. Series production of control systems using standardized valve blocks requires a lot of effort and is expensive.
Further, control devices equipped with standardized valve blocks are heavy and in many cases imply undesirably large space requirements which is a disadvantage. This is due to the fact that special devices are needed in order to connect the standardized inlets and outlets of the valve blocks with the inlets and outlets of the other parts of the control device.